For the gate driver circuit used in small-sized display panel, the double-side-and-single-drive structure (that is, two independent gate driver circuits are disposed on two opposite sides of the display panel and for driving the odd-numbered gate lines and even-numbered gate lines, respectively) is usually adopted due to the specific display panel configuration. In addition, a source driver, for providing data voltages to the pixels of the display panel, is disposed either on the top or bottom of the display panel. Specifically, if the source driver circuit is disposed on the top of the display panel, driving the gate lines by the gate driver circuits in a sequence from top to bottom is so-called forward scan; alternatively, driving the gate lines in a sequence from bottom to top is so-called backward scan.
In order to pre-charge the next column of pixels, the timing sequences of the gate pulses provided to each two adjacent gate lines respectively driven by the two gate driver circuits disposed on two opposite sides of the display panel have an overlap design. However, because the gate pulse overlap design, a feed-through voltage may be generated and the data voltage stored in the pixel capacitor may be affected by the generated feed-through voltage when the forward scan or the backward scan is performed. In general, the various-degree effect of the feed-through voltage on the data voltage can be compensated by the adjustment of the voltage difference between the gamma voltage and the common voltage (Vcom). In addition, the feed-through voltage resulted by the backward scan has a greater effect on the data voltage stored in the pixel circuit, compared with the feed-through voltage resulted by the forward scan. Thus, for the compensation of the various effects of the feed-through voltages for both of the forward scan and the backward scan, more numbers of setting value of gamma voltage and common voltage are required. In addition, more tuning time is also required if the gamma voltage and the common voltage have a relatively large degree to be adjusted.